1. Field of the Invention
The present invention relates to a structure for attaching a resin cowling, a resin fender, a resin cover, or other resin parts to a vehicle body of a motorcycle with a bolt.
2. Description of the Related Art
Conventionally, in a case where various resin parts are attached to a vehicle body, in order to prevent fastening pressure from becoming excessive due to too much fastening of a bolt, a metal collar is insert-molded into an attached portion (bolt insertion hole) of the resin part so as to be used as a spacer. However, when the collar is insert-molded, manufacture of the resin part takes a lot of effort, and the collar is required separately from the bolt as an attaching part.
Meanwhile, recently, there is employed an attachment structure which omits the insert collar by using a shoulder bolt in which a large diameter portion is formed in a threaded shaft portion of the bolt.
FIG. 8 shows a conventional attachment structure for a resin part 110 utilizing a shoulder bolt 140, and the shoulder bolt 140 integrally has a threaded shaft portion 141 in which a male screw is formed, a head portion 142, a washer 144, and a large diameter portion 143 thicker than the threaded shaft portion 141. A nut 131 is press-fitted and fixed to an attaching portion 130 of a vehicle body frame 101, and a bolt insertion hole 135 having an inner diameter into which the large diameter portion 143 of the shoulder bolt 140 is insertable is formed in an attached portion 120 of the resin part 110.
As a conventional technical document of an attachment structure for a resin part utilizing a shoulder bolt, there is JP 2011-58548 A.
With the conventional structure of FIG. 8, a diameter of the bolt insertion hole 135 formed in the resin part is larger than a diameter of the threaded shaft portion 141 of the shoulder bolt 140. Thus, at the time of assembling, a shoulder surface 143a of the large diameter portion 143 may come upon a seating surface 134 of a peripheral portion of the bolt insertion hole 135 as shown in the figure. In this case, a position of the shoulder bolt 140 and a position of the resin part 110 are required to be corrected, so that an assembling task of the resin part such as a cowling takes a lot of effort.
An object of the present invention is to provide an attachment structure for a resin part of a motorcycle in which at the time of assembling, a shoulder surface of a shoulder bolt does not come upon a seating surface in a periphery of a bolt insertion hole and a large diameter portion of the shoulder bolt can promptly be inserted into the bolt insertion hole.